convert external stylesheet to inline css

[siofont]

Hi,
I apologize if this is not the correct group to post this.

We are an Alumni association from a Spanish University. We are sending a monthly
email newsletter with some css styles. We use Dreamweaver to create it and
Mozilla Thunderbird to send it.

We found that members with webmail readers as Gmail, Yahoo Mail and Hotmail and
the University own webmail, are loosing all css styles.

After some Google research, I understand that popular webmails change or delete
content between <headtags. General recommendation is to embed css styles in
html tags.

I want to ask for a tool/parser/software/easy way that allows us to do this
embedding automatically and avoid to do it manually each month. I have checked
some newsletter software (from tucows), but without success (they are good for
sending newsletters/spam to a long email list, but don't offer this css
embedding)

Thanks in advance

sioFont